by all means，by no means
這一組詞並非同義詞，而是具有鮮明對立意義的反義語。它們帶有強烈的感情色彩，在文句中起加強語勢的作用。
By all means的意思是「一定」、「無論如何」、「用一切手段」。例：
You must bring him here by all means.
你們一定要設法把他帶到這裡來。
This project must be realized by all means.
這個規劃必須要實現。
You should by all means warn him before he leaves for Singapore.
你務必在他去新加坡之前提醒他。
By all means亦可用於回答，表示有禮貌的同意，作「好的」、「當然可以」解。例：
May I have one?—Yes，by all means.
我可以拿一個嗎?——當然可以。
By no means的意思是「決不」，相當於not at all。例：
She is by no means bright.
她一點兒也不聰明。
I will by no means consent.
我決不同意。
The first step will take quite a long time and can by no means be accomplished overnight.
第一步的時間是相當地長，決不是一朝一夕所能完成的。
請注意下列三點：
(一)by all means和by no means的 means永遠用複數形式，「s」不能丟掉。
(二)by all means與by all manner of means通用;by no means 可與 by no manner of means換用，但後者只作特別強調，遠不如前者用得普遍。
(三)by any means的意思是「總之」;by some means (or other)的意思是「用某種方式(或方法)」;不要把它們與by all means或by no means混淆。